StarShine: It's important to set limits not just for one's own piece of mind & private space, but to teach respect for same. It helps to establish some ground rules & to be consistent.
With 4 kids, their friends & a hubby who likes to turn up the sound on the telly & stereo, I had to set limits years ago. I insisted my kids be considerate of family members & of guests; to respect each other's private space including not entering anyone's room without permission. A closed door automatically means do not disturb, so knock first. If I am on the phone, whatever it is will have to wait as long as it is not an emergency (I explained what an emergency is & what it isn't). If anyone is inconsiderate of me during "my time" or phone call or whatever, that person is denied a privilege in accordance with the "offense", such as having friends over, the use of the phone, etc.
Fortunately, hubby has been very supportive & runs interference. Even when he's not home, I only have to mention I'm meditating, praying or doing a reading.
To avoid problems, I try to let my family know what my plans are ahead of time. If I meditate in my bedroom, I shut the door. Since I do readings in my kitchen, I let my family know so they can use the kitchen ahead of time. The kitchen has a door which I sometimes shut during an in-person session, depending on what is going on in the house. The family knows when I am busy they have to answer the phone or the door.
When the kids were younger, their bedtime was "grownup time". That was usually when I had some time to myself. Now that they are older, it's easier.
Being firm about what your expectations are & how it could work to benefit everyone could be the beginning of an investment in your own time & space. Good luck!